Just take the OBR times and work out the average for any group. As Josh says, it may be a case that you look at e.g Top 10 or Top 20 participants in the group to calculate that - but if it's an average time of the group then you can easily do it regardless of total participants...

Certainly you can work out which group is faster on average - in the same way we work out which team is faster on average here:

/gb/Stats.asp?type=bigrace&stype=teams#scroll

Just take the OBR times and work out the average for any group. As Josh says, it may be a case that you look at e.g Top 10 or Top 20 participants in the group to calculate that - but if it's an average time of the group then you can easily do it regardless of total participants...

I know you can calculate yourself from the 'class list and/or race summary all groups. But the list you showed is exactly the idea but than per group. Stupid I missed that!